Brassieres are worn not only to provide support for women's breasts, but also to enhance the shape of the breasts within the brassieres, the portion of the breasts above the breasts and the cleavage between the breasts.
Push-up bras are designed to shape and elevate the breasts. Push-up bras usually contain a rubber pad received in a pocket in the lower front panels of the bra cups. The pad was formed by molding into a complex arcuate shape. Rubber pads were both stiff and uncomfortable. Rubber pads also caused insecurity due to straying of the pads. Other push-up bras used a more yielding silicone foam and some use Nylon (polyamide) padding to shape and lift.
Push-up bras with liquid filled envelopes have recently appeared on the market. Silicone oil liquids are very expensive and are hard to seal. Hydrocarbon oils have also been utilized as the liquid either alone or in a mixture with water. Hydrocarbons can attack the envelope. The liquids in the envelope are heated to body temperature of about 99.degree. F. At this temperature, evaporation is increased and the hydrocarbon vapors can permeate through the wall of the envelope, creating offensive, unpleasant odors. Furthermore, water vapor is also able to permeate through the wall of the envelope decreasing the liquid volume in the envelope. The envelope could rupture or impact or when pierced by a sharp object causing embarrassment, discomfort and destruction of the pad.
______________________________________ List of References Patentee Patent No. ______________________________________ Block, et al. 3,620,222 Kirby, et al. 3,845,507 Miller 5,235,974 ______________________________________